Nuclear energy is possibly used in real life by controlling so that a lot of energy instantaneously emitted at the time of nuclear explosion is released slowly as intended. By using this in nuclear power generation, thermal energy is used as power.
A nuclear reactor used for the nuclear power generation is an apparatus for using thermal energy generated in nuclear fission as power by controlling chain reactions such that lots of mass defect energy instantaneously generated from a chain nuclear fission reaction can be released. While a typical thermal furnace uses combustion heat of a material, the nuclear reactor uses the mass defect energy generated from the nuclear fission reaction. However, when the nuclear fission occurs in the nuclear reactor, not only lots of energy but also radiations are generated. The radiations include alpha rays, beta rays, X-rays, gamma rays, and neutrons, and various rays may compositely exist according to an environment.
In alpha radiation, two electrons are removed from a helium ion (He) and the remaining helium nucleus flows very rapidly. An alpha ray has a long wavelength and high reactivity with other materials, and accordingly allows ionization such that atoms or molecules in a material are broken, photosensitive phenomenon such that a chemical reaction occurs with photosensitive paper like a film, or fluorescence such that a light is emitted by reacting with a fluorescent material. However, an alpha ray has low penetrability so that it cannot penetrate even a sheet of paper. In addition, since they react well with other materials, alpha rays are frequently used in plant gene manipulation, and plant growth promotion and inhibition.
Beta radiation involves very rapid flow of electrons and has a longer wavelength than alpha radiation. Accordingly, ionization, photosensitive phenomenon, and fluorescence less frequently occur. The penetrability is a little higher so that paper or plastic is penetrable but a thin iron plate is not. Accordingly, beta radiation is used in measuring a thickness of plastic due to proper penetrability.
X-rays are a type of radiation that was accidentally found while Rontgen irradiated a metal with a cathode-ray, and have weaker but higher penetrability than gamma rays. X-rays are used very efficiently in the medical field, and also variously used in physics, biology, and chemistry, etc.
Gamma radiation corresponds to an electromagnetic wave, but not to a particle. Accordingly, a gamma ray has very low reaction with other materials but higher penetrability so that it can easily penetrate thin metal. Gamma rays cannot penetrate lead having a thickness of 30 cm or more or a concrete wall having a thickness of 1 m or more. In addition, gamma rays are mainly used in industry and the medical field. In particular, gamma rays are also used in nondestructive testing, metal thickness measurement, impurity concentration testing, or radiation treatment of a cancer patient, etc.
A neutron is an elementary particle. As a constituent element of a nucleus together with a proton, it has the almost the same mass as the proton and maintains neutrality without electricity. In addition, the neutron has such a large penetrability for a material that it is used in destructing the nucleus.
A typical single radiation sensor measures only single radiation, and, when different radiations are measured, different radiation sensors are necessary. In addition, a cost is high in forming a measuring instrument with different sensors mounted therein. A radiation sensor includes a gas type, a scintillation type, or a semiconductor type, and each type requires different electronic circuit configuration from each other.